Even the most well-crafted initiatives from architects and other professionals using post-Katrina New Orleans as a kind of urban planning laboratory will fail if they can't earn the trust of a diverse coalition of supporters, two local social justice advocates told a national conference of planners Saturday.

Nolan Rollins, president of the Urban League of Greater New Orleans, and Michael Cowan, head of the nonprofit group Common Good and an assistant to Loyola University's president, told a crowd of nearly 100 planners that distrust among different groups of people in a politically divided city is New Orleans' biggest problem.

"It is bigger than racism ... and any geographic vulnerability" to hurricane-related flooding, Cowan said during the morning session of "New Orleans Under Reconstruction: The Crisis of Planning."

"All the planning in the world can't be implemented" if different groups of people in the city disagree about a plan's benefits to them, Rollins added.

The conference, organized by Tulane's School of Architecture, met Friday and Saturday at the university's Lavin-Bernick Center.

Preceding a series of presentations on blueprints for the future of New Orleans, Rollins and Cowan portrayed their presentation as an offering of practical advice that planners should fold into their efforts.

David Dixon, the chief author of New Orleans' proposed master plan for development during the next two decades, lauded Rollins' and Cowan's comments as "fundamental."

A mix of local and out-of-town planning professors and practitioners also heard details about a grim situation that anyone aiming to reinvent some of New Orleans' neighborhoods must deal with, according to a Columbia University researcher.

Laura Kurgan cited an analysis she authored showing that almost 13 percent of New Orleans residents sentenced in 2007 to state Department of Corrections institutions came from Central City -- an area then home to about 5 percent of the city's population.

Each year since 2003, the state has spent more than $1 million to imprison convicts from Central City alone.

"Planning processes haven't taken the obstacles that kind of situation presents into account," Kurgan said.

Kurgan's findings and call to action drew the most applause of the conference's morning presentations.

During an open-microphone forum at the end of the morning session, the president of the Louisiana Endowment for the Humanities said there has been enough planning talk. "Who, ultimately, is going to have the power to enact any plan?" asked Michael Sartisky.

Cowan said any honest, effective local government would.

Meanwhile, Tulane urban sociologist Kevin Fox Gotham said that diverting money from what he portrayed as failed wars in Iraq and Afghanistan to New Orleans and the rest of the Gulf Coast would buoy post-Katrina redevelopment initiatives.

"Really, what are we getting from (the wars)?" Gotham asked.

While some sat quietly, many audience members clapped. At least one whooped.

Ramon Antonio Vargas can be reached at rvargas@timespicayune.com or 504.826.3371.